The primary structural elements of large aircrafts are typically made from metal or composite materials. For example, the fuselage shells of such aircraft may typically be manufactured from high-strength aluminum alloys or fiber-reinforced resin materials that have relatively high strength-to-weight ratios.
An aircraft may include two or more fuselage, i.e., shell, sections, which are bridged and fastened together circumferentially at a splice joint to interconnect the fuselage sections and form the complete fuselage structure. To precisely install the integration joints, the fuselage sections are aligned and attachment holes are drilled through the connecting splice plates and the underlying shell structure. For example, adjacent fuselage sections may be joined by a splice consisting of a frame or bulkhead that is positioned in the interior of the fuselage and bridges between adjacent fuselage section stringers. A plurality of fittings extend through the frame and facilitate the continuity of the fuselage sections. As another example, adjacent fuselage sections may be integrated together by the splice plate and a plurality of splice fittings attached between a pair of adjacent fuselage sections to bridge the interface between the adjacent fuselage sections. Generally the splice plate is flat and forms a flat splice chord that extends across the splice joint. Depending upon the type of splice joint, the assembly may require a plurality of mouse holes disposed in the frame or bulkhead through which extend the splice fittings.
Typically, a splice fitting may be formed of a metallic material, such as titanium. Since titanium is a relatively expensive material, the material and manufacturing costs associated with a titanium splice fitting may increase the costs associated with production of the aircraft.
Additionally, fuselage sections may splice together by a plurality of fasteners that extend through the frame to connect the frame to the fuselage sections and a plurality of fasteners that extend through the splice fittings to connect the fittings to the fuselage sections. In order to install the fasteners, a plurality of attachment holes must be drilled through the splice for receiving the fasteners. A disadvantage of such an assembly process is that the drilling of holes through a dissimilar material stack that contain titanium splice fittings takes a significant amount of time, thereby increasing the time required to assemble the fuselage sections as well as the labor costs associated with such assembly. Furthermore, the holes drilled through a splice fitting made of titanium or other metallic material generally require the parts to be separated and deburred, thereby further adding to the time and costs associated with the assembly of the fuselage. Another disadvantage of such an assembly process is that shims may be required to align the fuselage section and fit the splice fittings along the joint interface, thereby adding even more time and cost.
Accordingly, those skilled in the art continue with research and development efforts in the field of joining shell structures, particularly in the field of aircraft assembly.